Laser receiver, lidar and method for distance detection of an object point

Abstract

The application relates to a laser receiver, a laser radar and a method for detecting the distance of a point, and belongs to the technical field of sensors. The laser receiver comprises a receiver body, a light splitting component and a detection component, and the light splitting component and the detection component are installed inside the receiver body. The light inlet end of the light splitting component is located on the incident light path of the receiver body. The light inlet end of the detection component is located on the light splitting exit light path of the light splitting component. The laser receiver provided by the application can obviously reduce the probability that the detection component is excited by ambient light before the target light arrives, thereby effectively reducing the probability that the processor of the laser radar misjudges the ambient light as the target light, and the detection accuracy of the laser radar is improved.

Description

Technical Field

[0001] This application relates to the field of sensor technology, specifically to a laser receiver, a lidar, and a method for detecting the distance to an object point. Background Technology

[0002] The laser receiver is an important component of lidar. It receives the signal light emitted by the laser emitter and reflected by an object. After receiving the signal light, the laser receiver sends a voltage level to the lidar's processor, which then determines relevant information about the signal light (e.g., distance, angle).

[0003] In laser receivers, single-photon avalanche photodiodes (SPADs) are typically used as photon detectors. After being excited by a signal light, the SPAD sends a corresponding electrical signal to the lidar processor, which then performs calculations related to that signal light (calculating the object point's position). The probability of the SPAD being excited by the signal light is related to the signal light intensity; generally, the stronger the measured signal light, the higher the probability of the SPAD being excited.

[0004] During the operation of a lidar system, at the beginning of each detection cycle, the laser emitter emits a signal light. The processor determines the distance between the object point reflecting the signal light and the lidar based on the time it takes for the laser receiver to receive the signal light. Generally, the processor determines the time when the SPAD (Spectrum Optical Deposition Device) is first excited within the detection cycle as the time when the laser receiver receives the signal light. However, in practice, ambient light constantly enters the laser receiver before it detects the signal light, and this ambient light has a certain probability of exciting the SPAD. Therefore, the time when the laser receiver receives the signal light, as calculated by the processor, will be inaccurate, thus reducing the detection accuracy of the lidar. Summary of the Invention

[0005] This application provides a laser receiver, a lidar, and a method for detecting the distance to an object point, which can solve the technical problems existing in related technologies. The technical solution of the laser receiver, lidar, and method for detecting the distance to an object point is as follows:

[0006] In a first aspect, embodiments of this application provide a laser receiver, which includes a receiver body, a beam splitter, and a detector. The beam splitter and the detector are installed inside the receiver body. The incident light end of the beam splitter is located on the incident light path of the receiver body. The incident light end of the detector is located on the beam splitting and exiting light path of the beam splitter.

[0007] In one possible implementation, the laser receiver further includes a signal analysis component electrically connected to the detection component.

[0008] In one possible implementation, the laser receiver includes multiple detection components and multiple beam-splitting components. The input end of the first beam-splitting component is located on the incident light path of the receiver body. At least one input end of another beam-splitting component is present on the output light path of each beam-splitting component other than the second beam-splitting component; the first and second beam-splitting components are different beam-splitting components among the multiple beam-splitting components. Each detection component is located on the output light path of any beam-splitting component where no other beam-splitting component is present.

[0009] In one possible implementation, all beam-splitting components in the laser receiver have detection components on the beam-splitting output path of other beam-splitting components.

[0010] In one possible implementation, each beam-splitting component in the laser receiver has two beam-splitting output paths. One beam-splitting output path of each beam-splitting component (except the second beam-splitting component) contains the input end of another beam-splitting component, and the other beam-splitting output path contains one of the aforementioned detection components. The second beam-splitting component has one detection component in each of its two beam-splitting output paths.

[0011] In one possible implementation, the laser receiver body includes a housing and an incident lens. A beam splitter and a detector are mounted inside the housing. The incident lens is mounted at the light inlet of the housing.

[0012] In one possible implementation, the incident lens of the laser receiver includes a first diverging lens and a filter stacked together.

[0013] In one possible implementation, the detection component of the laser receiver includes a photon detector and a converging lens, with the converging lens located at the light inlet of the photon detector.

[0014] In one possible implementation, the beam-splitting component of the laser receiver is a beam splitter.

[0015] Secondly, embodiments of this application also provide a lidar, which includes a laser receiver as described in the first aspect and its possible implementations.

[0016] Thirdly, embodiments of this application also provide a method for detecting object distance, which is applied in a device including the laser receiver described in the first aspect. The method includes:

[0017] The beam splitter separates the signal light entering the laser receiver;

[0018] The detection component receives the split signal light, and when excited by the split signal light, it sends an excitation signal to the signal analysis component.

[0019] The signal analysis unit counts the number of excitations corresponding to different object point distances for each detector based on the excitation signal sent by each detector. Based on the number of excitations corresponding to different object point distances for each detector, the total number of excitations corresponding to each object point distance is determined. Based on the total number of excitations corresponding to each object point distance, the object point distance is determined as the detection result.

[0020] The technical solutions provided by the embodiments of this application have at least the following beneficial effects:

[0021] This application provides a laser receiver, which includes a receiver body, a beam splitter, and a detection component. The beam splitter is installed inside the receiver body and can split the incident light beam into multiple outgoing beams, with the intensity of the outgoing beams significantly reduced compared to the incident light. Before the laser receiver detects the signal light, ambient light enters the laser receiver first. The ambient light is split into multiple beams by the beam splitter, significantly reducing the probability that the ambient light will excite the detection component. This significantly reduces the probability that the detection component will be excited by the ambient light before the signal light arrives, thus significantly improving the accuracy of the laser receiver's signal light reception time as determined by the processor. Therefore, the detection accuracy of the lidar is improved.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a graph illustrating the statistical results of photon event counts in an embodiment of this application;

[0025] Figure 2 This is a graph illustrating the statistical results of photon event counts in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application;

[0027] Figure 4 This is a schematic diagram of the structure of a receiver body shown in an embodiment of this application;

[0028] Figure 5 This is a schematic diagram of the structure of an entrance lens shown in an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of the structure of a detection component shown in an embodiment of this application;

[0030] Figure 7 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application;

[0031] Figure 8 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application;

[0032] Figure 9 This is a graph illustrating the statistical results of photon event counts in an embodiment of this application;

[0033] Figure 10 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application;

[0034] Figure 11 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application;

[0035] Figure 12 This is a schematic diagram of the structure of a laser receiver shown in an embodiment of this application.

[0036] Legend

[0037] 1. Receiver body; 11. Housing; 12. Entrance lens; 121. First diverging lens; 122. Filter; 123. Second diverging lens; 124. Filter layer; 2. Beam splitting component; 21. First beam splitting component; 22. Second beam splitting component; 3. Detection component; 31. Photon detector; 32. Converging lens; 4. Signal analysis component. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0039] A lidar system mainly consists of a transmitting component, a receiving component, and a processor. After the transmitter emits a target light signal, the receiver receives the target light signal. The receiver converts the received light signal into an electrical signal and sends it to the lidar's processor, which then determines relevant information about the light signal (e.g., distance information, angle information, etc.). The lidar's receiver can be a single point detector or multiple single point detectors arranged according to a certain rule. The single point detector can be the laser receiver provided in this application.

[0040] Typically, laser receivers use SPADs as photon detectors. When using a SPAD-based lidar system for target detection, it needs to repeatedly emit light signals at the same location multiple times. The number of times the SPAD is excited by the reflected light signals (i.e., the number of photon events) is then counted. This statistical result is used to accurately characterize the echo signal, thus determining the location of the object point. In the absence of ambient light or with very weak ambient light, the SPAD is primarily excited by the echo signal. Assuming an object point exists 50 meters from the laser receiver, after the lidar repeatedly emits light signals, the statistical result of the number of photon events obtained by the laser receiver in the absence of ambient light is as follows: Figure 1 As shown (due to the large amount of data detected by the laser receiver, the horizontal axis in the statistical chart is quite dense).

[0041] However, due to the extremely high gain and sensitivity of SPADs, they are highly sensitive to ambient light. In the presence of ambient light, the SPAD is repeatedly excited by the ambient light before the echo signal arrives. Assuming an object point exists 50 meters from the laser receiver, after the lidar repeatedly emits light signals, the statistical results of the number of photon events affected by ambient light obtained by the laser receiver are as follows: Figure 2 As shown (due to the large amount of data detected by the laser receiver, the horizontal axis in the statistical chart is quite dense).

[0042] From the above Figure 1 and Figure 2 It is evident that in laser receivers using SPADs, ambient light significantly alters the statistical characteristics of SPAD photon events, leading to inaccurate characterization of echo signals, inability to determine object location, and sometimes even saturation of the SPAD device due to ambient light, rendering the laser echo signal undetectable. Therefore, this application provides a laser receiver that effectively reduces the impact of ambient light on the laser receiver; the detailed solution is as follows.

[0043] This application provides a laser receiver, the corresponding structure of which is as follows: Figure 2 As shown, the laser receiver includes a receiver body 1, a beam splitter 2, and a detector 3. The beam splitter 2 and the detector 3 are installed inside the receiver body 1. The light input end of the beam splitter 2 is located on the incident light path of the receiver body 1. The light input end of the detector 3 is located on the beam output path of the beam splitter 2.

[0044] The following is a detailed description of each component in the laser receiver:

[0045] Receiver body 1

[0046] The receiver body 1 may include a housing 11 and an incident lens 12, with the corresponding structure as follows: Figure 3As shown. The housing 11 is provided with a light inlet, the light inlet mirror 12 is installed at the light inlet of the housing 11, and the beam splitter 2, the detector 3 and the signal analysis 4 are installed inside the housing 11 of the receiver body 1.

[0047] The housing 11 can also be used to isolate light outside the detection range of the laser receiver 1, thereby preventing non-target light from interfering with the detection component 3. The housing 11 can also absorb non-target light inside the receiver 1; therefore, the inner surface of the housing 11 can be a dark color such as black. To better absorb excess light inside the receiver 11, a light-absorbing coating can be applied to the inner surface of the housing 11, and light-absorbing elements can also be installed.

[0048] The incident lens 12 can be directly mounted on the housing 11 of the receiver body 1 using methods such as snap-fit, adhesive bonding, or threaded connection. The incident lens 12 includes a first diverging lens 121 and a filter 122 stacked together, with the corresponding structure as shown below. Figure 3 As shown. The first diverging lens 121 is installed at the light inlet of the housing 11, close to the beam splitter 2. The filter 122 is installed at the light inlet of the housing 11, away from the beam splitter 2.

[0049] The first diverging lens 121 can adjust the propagation direction of the incident light rays to a direction parallel to the principal optical axis of the first diverging lens 121, such as... Figure 4 As shown, this increases the receiving range (receiving angle) of the laser receiver for receiving external light, and then allows the adjusted light to propagate towards the beam splitter 2. The first diverging lens 121 can be a single aspherical lens or a lens group composed of multiple aspherical lenses.

[0050] The filter 122 can be used to filter optical signals of non-signal wavelengths, and its passband can be the frequency range of infrared light. The frequency range of the passband of the filter 122 can also be set to the frequency range of the light emitted by the laser emitter used in conjunction with the laser receiver, or it can be set according to actual detection requirements. The filter 122 can also be replaced by a filter layer disposed on the outer surface of the lens (the surface away from the beam splitter). The filter layer can be an adhesive filter film or a sprayed filter coating.

[0051] In addition to being installed at the entrance lens 12, the filter 122 can also be installed in the incident light path and / or the post-splitting output light path of each beam splitting component 2, or it can be directly installed at the detector component 3.

[0052] Spectrometer 2

[0053] Beam splitter 2 may have one light-inlet end and multiple light-outlet ends, used to split a beam of light incident on the light-inlet end into multiple beams according to a certain beam splitting ratio. Beam splitter 2 may be a component with an independent housing or a component without a housing. If beam splitter 2 has a housing, the light-inlet end and the light-outlet end of beam splitter 2 may be light-inlet holes and light-outlet holes opened at corresponding positions on the housing. If beam splitter 2 does not have a housing, the light-inlet end of beam splitter 2 may be a pre-designated light-inlet position on beam splitter 2, and the light-outlet end may be a pre-designated light-outlet position on beam splitter 2.

[0054] The beam splitter 2 has a certain detection range (or detection angle), meaning that the direction of light incident at the light-incident end has a certain angular range. The beam splitter 2 is located inside the receiver body 1, and its light incident direction matches the direction of the light incident optical path of the receiver body 1, that is, the direction of the light incident optical path is within the detection range of the beam splitter 2.

[0055] The beam splitter 2 can be directly mounted on the housing 11 of the receiver body by means of snap-fit, adhesive bonding, or other methods, or it can be indirectly mounted on the housing 11 by means of an intermediate component, such as a bracket. The laser receiver may include one beam splitter 2 or multiple beam splitters 2.

[0056] Among them, the beam splitting component 2 can be a beam splitter. The beam splitter can be a prism beam splitter, a single-piece flat beam splitter, or a beam splitter group composed of multiple flat beam splitters.

[0057] The beam splitting ratio of the beam splitting component 2 can be a fixed beam splitting ratio, for example, the reflectivity to refractive index of a flat beam splitter is 1:1, the reflectivity to refractive index of a flat beam splitter is 1:3, and so on. The beam splitting ratio of the beam splitting component 2 can also be a variable beam splitting ratio, for example, a step beam splitting ratio, a continuously variable beam splitting ratio, etc.

[0058] Detection component 3

[0059] The detection component 3 includes a photon detector 31 and a converging lens 32, with the corresponding structures as follows: Figure 5 As shown. The light-incident end of the detector component 3 is located on the beam-splitting output light path of the beam-splitting component 3, and the central axis of the detector component 3 coincides with the optical axis of the converging lens 32. The detector component 3 can be directly installed on the bottom of the housing 11 of the receiver body by means of snap-fit, adhesive bonding, etc., or it can be indirectly installed in the housing 11 by means of an intermediate component, such as a bracket.

[0060] The converging lens 32 is located on the beam-splitting output path of the beam-splitting component 3 and at the entrance of the photon detector 31. The optical axis of the converging lens 32 coincides with the central axis of the beam-splitting output path in which the converging lens 32 is located. The beam diameter of the light rays split by the beam-splitting component 2 is larger than the diameter of the entrance of the photon detector 31. Therefore, it is necessary to use the converging lens 32 to converge as much of the light rays split by the beam-splitting component 2 as possible onto the photon detector 31. The converging lens 32 can be a single aspherical convex lens or a lens group composed of multiple aspherical convex lenses.

[0061] The photon detector 31 is used to detect the received light. Each time the photon detector 31 is excited by light, it generates an electrical signal indicating that it has been triggered. This electrical signal can be a high level or a group of levels. The excitation of the photon detector 31 is recorded as a photon event, and the number of times it is excited is recorded as the photon event count. The photon detector 31 can be a semiconductor device such as a single-photon avalanche photodiode (SAPD).

[0062] Signal Analysis Component 4

[0063] The laser receiver may also include a signal analysis component 4. The signal analysis component 4 can be installed inside the receiver body 1, and is electrically connected to the detection component 3, with the corresponding structure as shown below. Figure 6 As shown. The signal analysis component 4 is used to perform statistical analysis on the photons detected by the detection component 3, and can be a chip, chipset, or integrated circuit. The signal analysis component 4 can also be installed outside the receiver body; for example, the signal analysis component 4 is the processor of a lidar composed of a laser receiver, etc.

[0064] A lidar system can include one or more laser receivers. When a lidar system includes one laser receiver, each laser receiver corresponds to a signal analysis unit 4. This signal analysis unit 4 can be the lidar's processor or a separate component electrically connected to the lidar's processor. When a lidar system includes multiple laser receivers, each laser receiver can correspond to a separate signal analysis unit 4, or they can share a single signal analysis unit 4. This shared signal analysis unit 4 can be the lidar's processor or a separate component electrically connected to the lidar's processor.

[0065] The signal analysis unit 4 can acquire the electrical signals transmitted by the photon detector 31, thereby determining the number of times the photon detector 31 is excited per unit time, i.e., the number of photon events. The signal analysis unit 4 can statistically analyze the number of photon events in all photon detectors 31 per unit time using a specific mathematical method, such as calculating the sum of all photon event counts, calculating the average of the photon event counts, etc. A preset threshold for the number of photon events can be set in the signal analysis unit 4. When the statistical result is greater than or equal to the threshold, the detected light is considered to be the target light, and the distance to the object point corresponding to the target light is determined. When the statistical result is less than the threshold, the detected light is considered not to be the target light. For example, the preset threshold for the number of photon events could be 100, 200, etc.

[0066] This application provides a method for detecting the distance to an object point, which is applied in a laser receiver. The laser receiver includes a receiver body 1, a beam splitter 2, multiple detectors 3, and a signal analysis unit 4. The beam splitter 2 and the detectors 3 are installed inside the receiver body 1. The light-incident end of the beam splitter 2 is located on the incident light path of the receiver body 1, and the light-incident end of the detectors 3 is located on the beam-splitting outgoing light path of the beam splitter 2. The signal analysis unit 4 is electrically connected to the detectors 3.

[0067] A laser emitter periodically emits multiple light signals from the same location. The interval between each emitted light signal and the most recent emitted light signal is called a detection cycle. In each detection cycle, the SPAD is excited at most once, meaning that the SPAD can only determine the distance to one object point in each detection cycle.

[0068] When the lidar starts working, the laser emitter emits a light signal, and the laser receiver begins to detect the received light. External light enters the receiver body 1 of the laser receiver through the entrance lens 12. Inside the receiver body 1, the external light is split by the beam splitter 2 and then propagates to the detection unit 3. The photon detector 31 in the detection unit 3 is excited by the received light and sends an electrical signal to the signal analysis unit 4. Each time an electrical signal is sent, it represents one excitation of the photon detector 31. The electrical signals sent at different times correspond to different object point distances.

[0069] First, the signal analysis unit 4 counts the number of excitations corresponding to different object point distances within a certain time period for each of the corresponding detection units 3. Second, based on the number of excitations counted for each object point distance by each detection unit 3, the signal analysis unit 4 determines the total number of excitations corresponding to each object point distance in the entire laser receiver. Then, based on the total number of excitations corresponding to each object point distance and a pre-set photon time threshold, the signal analysis unit 4 determines the object point distance that meets the conditions, i.e., the detection result of the laser receiver.

[0070] In this embodiment, the laser receiver may include one or more beam-splitting components 2. The following is a detailed description of the case with one beam-splitting component 2. The incident lens 12 of the laser receiver may be mounted at the light inlet of the receiver body 1, and the beam-splitting component 2 and the detection component 3 may be mounted inside the receiver body. The optical axis of the incident lens 12 on the receiver body 1 may pass through the center point of the beam-splitting component 2 and coincide with the central axis of the incident light. The laser receiver may include one beam-splitting component 2 and at least one detection component 3. Two possible cases are given below:

[0071] Scenario 1

[0072] The laser receiver includes a beam-splitting component 2 and a detection component 3, with the corresponding structures as follows: Figure 7 As shown.

[0073] The light-incident end of the beam splitter 2 is located on the incident light path of the receiver body 1. The incident light path of the beam splitter 2 coincides with the incident light path of the receiver body 1 and has the same direction. The beam splitter 2 may also include multiple beam-splitting exit light paths, with only one beam-splitting exit light path containing a detector 3. The incident light path of the detector 3 coincides with the beam-splitting exit light path of the beam splitter 2 and has the same direction. The light in the beam-splitting exit light path where the detector 3 is not present can be absorbed by the housing 11, or by a light-absorbing element installed on the housing 11. A blocking component can also be provided at the light-emitting end of the beam splitter 2 to absorb the light.

[0074] Taking the beam splitter 2 as an example of a flat beam splitter, the corresponding structure is as follows: Figure 8 As shown.

[0075] A planar beam splitter is indirectly mounted inside the laser receiver body 1 via a bracket, and the angle between the mirror surface of the planar beam splitter and the central axis of the incident light path of the receiver body 1 is 45°. The beam splitting ratio of the planar beam splitter can be 1:1, splitting an incident light beam into two outgoing light beams, namely a reflected light beam and a refracted light beam, with the intensity of both the reflected and refracted light beams being half the intensity of the incident light beam. The path of the reflected light beam is perpendicular to the incident light path of the receiver body 1, while the path of the refracted light beam is parallel to the incident light path of the receiver body 1. A detector 3 is mounted on the housing 11, with its input end located on the reflected light path of the planar beam splitter, and the central axis of the detector 3 coinciding with the central axis of the reflected light path of the planar beam splitter.

[0076] When the incident light passes through the incident lens 12, the incident lens 12 filters out light of non-signal wavelengths, adjusts the propagation direction of the incident light to be parallel to the principal optical axis of the incident lens 12, and propagates into the interior of the receiver body 1, forming an incident light path. The incident light on this incident light path passes through the incident end of the planar beam splitter and reaches the mirror surface of the planar beam splitter. The planar beam splitter splits the incident light into reflected light and refracted light at a 1:1 beam splitting ratio. The refracted light of the planar beam splitter can be absorbed by the housing 11. The reflected light of the planar beam splitter serves as the incident light of the detection component 3, entering the detection component 3 through the incident end of the detection component 3. The converging lens 32 of the detection component 3 converges the incident light of the detection component 3 onto the photon detector 31 of the detection component 3. After being excited by the light, the photon detector 31 outputs an electrical signal indicating that it has been excited to the signal analysis component 4. The signal analysis component 4 acquires the number of times the photon detector 31 is excited per unit time, determines whether the beam of light includes the target light, and determines the object point distance corresponding to the target light based on the preset photon event threshold.

[0077] The aforementioned beam splitter 2 divides the incident ambient light and echo signal into reflected and refracted rays in a 1:1 ratio. After beam splitting, the intensity of the ambient light on any outgoing path is half that before splitting, and the intensity of the echo signal on any outgoing path is also half that before splitting. The probability of ambient light excitation of the SPAD is significantly reduced after beam splitting; however, the probability of echo signal excitation of the SPAD is not significantly reduced. For example, before splitting, the probability of ambient light excitation of the SPAD is 90%, and the probability of echo signal excitation of the SPAD is 95%; after splitting, the probability of ambient light excitation of the SPAD is 50%, and the probability of echo signal excitation of the SPAD is 85%. Based on the significant reduction in the probability of ambient light excitation of the SPAD after beam splitting, the statistical results of the number of photon events affected by ambient light are as follows: Figure 9 As shown (due to the large amount of data detected by the laser receiver, the horizontal axis in the statistical chart is quite dense).

[0078] in, Figure 9 and Figure 2 The incident rays can be considered to be the same. Figure 9 These are the statistical results of photon events obtained by the laser receiver after beam splitting. Figure 2 This is the statistical result of photon events obtained from the laser receiver before beam splitting. Figure 9 and Figure 2 It is evident that, after beam splitting, the number of SPAD excitations from ambient light is significantly reduced in the laser receiver, while the number of SPAD excitations from echo light signals is increased. Beam splitting allows for better differentiation between ambient light and echo light signals, enabling more accurate characterization of the echo light signal and thus more precise determination of the object point's location.

[0079] In addition to the fact that the light-incident end of the detection component 3 is located on the reflected light path of the flat beam splitter, the light-incident end of the detection component 3 can also be located on the refracted light path of the flat beam splitter. The corresponding structure and the detection process of the incident light are similar to those described above, and will not be repeated here.

[0080] Scenario 2

[0081] The laser receiver includes a beam-splitting component 2 and two detection components 3, with the corresponding structures as follows: Figure 10 As shown.

[0082] The light-incident end of the beam splitter 2 is located on the incident light path of the receiver body 1. The beam splitter 2 may include multiple beam-splitting outgoing light paths, and a detector 3 is present on each beam-splitting outgoing light path.

[0083] Taking the beam splitter 2 as an example of a flat beam splitter, the corresponding structure is as follows: Figure 10 As shown.

[0084] A planar beam splitter is indirectly mounted inside the laser receiver body 1 via a bracket, and the angle between the mirror surface of the planar beam splitter and the central axis of the incident light path of the receiver body 1 is 45°. The beam splitting ratio of the planar beam splitter can be 1:1, splitting an incident light beam into two outgoing light beams, namely a reflected light beam and a refracted light beam, with the intensity of both the reflected and refracted light beams being half the intensity of the incident light beam. The path of the reflected light beam is perpendicular to the incident light path of the receiver body 1, while the path of the refracted light beam is parallel to the incident light path of the receiver body 1. The laser receiver includes two detection components 3, which are respectively mounted on the housing 11. The light-incident ends of these two detection components 3 are located on the reflected and refracted light paths of the planar beam splitter, respectively, and the central axes of the detection components 3 coincide with the central axes of their respective splitting outgoing light paths.

[0085] When the incident light passes through the incident lens 12, the incident lens 12 filters out light of non-signal wavelengths, adjusts the propagation direction of the incident light to be parallel to the principal optical axis of the incident lens 12, and propagates into the interior of the receiver body 1, forming an incident light path. The incident light on this incident light path passes through the incident end of the planar beam splitter and reaches the reflecting surface of the planar beam splitter. The planar beam splitter splits the incident light into reflected light and refracted light at a 1:1 beam splitting ratio. The reflected light and refracted light from the planar beam splitter serve as the incident light for the two detector components 3, and enter the detector component 3 through the incident end of the detector component 3, respectively. The converging lens 32 of the detector component 3 converges the incident light of the detector component 3 onto the photon detector 31 of the detector component 3. After being excited by the light, the photon detector 31 outputs an electrical signal indicating that it has been excited to the signal analysis component 4. The signal analysis component 4 acquires the number of times the two photon detectors 31 are excited per unit time. Based on the preset calculation method and photon event threshold, it determines whether the beam of light includes the target light and determines the object point distance corresponding to the target light.

[0086] In addition to the two cases mentioned above, when the laser receiver includes a beam splitter 3, it may also include two or more detection components. The corresponding structure and the detection process for the incident light are similar to those described above, and will not be repeated here.

[0087] Compared to a structure containing only one detector element 3, a laser receiver with two detector elements 3 can acquire two detection results within one detection cycle. Laser receivers using SPADs often need to determine the target ray from multiple detection results; therefore, the number of detections required by a laser receiver with two detector elements 3 is half that required by a laser receiver with only one detector element 3. Thus, the more detector elements 3 there are, the more detections can be counted, and the higher the detection efficiency.

[0088] On the other hand, the signal analysis unit 4 statistically analyzes the detection results of multiple detection units 3, performs cross-validation and summary analysis, reduces systematic errors, and thus improves the confidence of the laser receiver detection results.

[0089] In this embodiment, the laser receiver may include one or more beam-splitting components 2. The following describes the case of multiple beam-splitting components 2 in detail. The incident lens 12 of the laser receiver may be installed at the light inlet of the receiver body 1, and the beam-splitting components 2 and the detection component 3 are installed inside the receiver body. The optical axis of the incident lens 12 on the receiver body 1 may pass through the center point of the beam-splitting component 2 and coincide with the central axis of the incident light path.

[0090] The laser receiver may include multiple beam-splitting components 2 and multiple detector components 3. The multiple beam-splitting components 2 may include a first beam-splitting component 21 and a second beam-splitting component 22, and may also include other beam-splitting components 2. The input end of the first beam-splitting component 21 is located on the incident light path of the receiver body 1, and the input end of the beam-splitting component 21 is present on at least one beam-splitting outgoing light path. The input end of the second beam-splitting component 22 is located on the beam-splitting outgoing light path of the beam-splitting component 21, and the input end of the detector component 3 is present on each beam-splitting outgoing light path of the second beam-splitting component 22. The input ends of the other beam-splitting components 2 are located on the beam-splitting outgoing light paths of beam-splitting components other than the second beam-splitting component 22, and the input end of the beam-splitting component 2 is present on at least one beam-splitting outgoing light path of the other beam-splitting components 2. Two possible scenarios are given below:

[0091] Scenario 1

[0092] In the beam splitter 2 of the laser receiver, there is an input end of beam splitter 2 in one beam splitting output path. In the beam splitting output paths of other beam splitters 2, there are detection components 3, with corresponding structures as follows: Figure 8 As shown.

[0093] In the laser receiver, the beam splitter 2 includes at least two beam-splitting output paths. Except for the second beam splitter 22, only one beam splitter 2 has an input end on its output path, while the other beam splitter output paths have input ends for the detectors 3. The second beam splitter 22 has input ends for the detectors 3 on all its beam splitter output paths.

[0094] Taking the beam splitter 2 as an example of a flat beam splitter, the corresponding structure is as follows: Figure 8 As shown.

[0095] The laser receiver includes three planar beam splitters, which are indirectly mounted inside the laser receiver body 1 via a bracket. The angle between the mirror surface of each planar beam splitter and the central axis of the incident light path of the receiver body 1 is 45°. The beam splitting ratio of the planar beam splitters can be 1:1, splitting an incident light beam into two outgoing beams: a reflected beam and a refracted beam. The intensity of both the reflected and refracted beams is half the intensity of the incident light. The path of the reflected beam is perpendicular to the incident light path of the receiver body 1, while the path of the refracted beam is parallel to the incident light path of the receiver body 1. Inside the receiver body 1, the planar beam splitter closer to the incident mirror 12 is the first planar beam splitter, and the planar beam splitter farther from the incident mirror 12 is the second planar beam splitter. Among the planar beam splitters except the second planar beam splitter, the incident end of the planar beam splitter is located on the refracted light path, and the incident end of the detection component 3 is located on the reflected light path. The incident ends of the detection component 3 are located on both the refracted and reflected light paths of the second planar beam splitter.

[0096] When external light passes through the incident lens 12, the incident lens 12 filters out light of non-signal wavelengths, adjusts the propagation direction of the incident light to be parallel to the principal optical axis of the incident lens 12, and propagates into the interior of the receiver body 1, forming an incident light path. The incident light on this incident light path passes through the incident end of the planar beam splitter and reaches the mirror surface of the planar beam splitter. The planar beam splitter splits the incident light into reflected light and refracted light at a 1:1 beam splitting ratio. In the planar beam splitters other than the second planar beam splitter, the reflected light serves as the incident light of the detector 3, and the refracted light serves as the incident light of the planar beam splitter. In the second planar beam splitter, both the reflected light and the refracted light serve as the incident light of the detector 3. The converging lens 32 of the detector 3 converges the incident light of the detector 3 onto the photon detector 31 of the detector 3. After being excited by light, the photon detector 31 outputs an electrical signal indicating that it has been triggered to the signal analysis unit 4. The signal analysis component 4 acquires the number of times each of the four photon detectors 31 is excited per unit time. Based on the preset calculation method and photon event threshold, it determines whether the beam of light includes the target light and determines the object point distance corresponding to the target light.

[0097] Scenario 2

[0098] In the multiple beam-splitting components 2 of the laser receiver, except for the second beam-splitting component 22, beam-splitting component 2 exists in the beam-splitting output path of each beam-splitting component 2, and the corresponding structure is as follows: Figure 9 As shown.

[0099] In the laser receiver, the beam splitter 2 includes at least two beam-splitting output optical paths. In all beam splitters 2 except the second beam splitter 22, the output optical paths all have an input end of the beam splitter 2. The output optical path of the second beam splitter 22 also has an input end of the detector 3.

[0100] Taking the beam splitter 2 as an example of a flat beam splitter, the corresponding structure is as follows: Figure 9 As shown.

[0101] The laser receiver includes two planar beam splitters, which are indirectly mounted inside the laser receiver body 1 via a bracket. The angle between the mirror surface of the planar beam splitter and the central axis of the incident light path of the receiver body 1 is 45°. The beam splitting ratio of the planar beam splitter can be 1:1, splitting an incident light beam into two outgoing light beams: a reflected beam and a refracted beam. The intensity of both the reflected and refracted beams is half the intensity of the incident light. The path of the reflected beam is perpendicular to the incident light path of the receiver body 1, while the path of the refracted beam is parallel to the incident light path of the receiver body 1. Inside the receiver body 1, the incident end of the first planar beam splitter is located on the incident light path of the receiver body 1, and the incident end of the detector element 3 is present on the outgoing light path of the second planar beam splitter. In the planar beam splitters other than the second planar beam splitter, the incident ends of the planar beam splitter are present on both the refracted and reflected light paths. The incident ends of the detector element 3 are present on both the refracted and reflected light paths of the second planar beam splitter.

[0102] When external light passes through the incident lens 12, the incident lens 12 filters out light of non-signal wavelengths, adjusts the propagation direction of the incident light to be parallel to the principal optical axis of the incident lens 12, and propagates into the interior of the receiver body 1, forming an incident light path. The incident light on this incident light path passes through the incident end of the planar beam splitter and reaches the mirror surface of the planar beam splitter. The planar beam splitter splits the incident light into reflected light and refracted light at a 1:1 beam splitting ratio. In the planar beam splitters other than the second planar beam splitter, the reflected light and refracted light serve as the incident light of the planar beam splitter. In the second planar beam splitter, both reflected light and refracted light serve as the incident light of the detection component 3. The converging lens 32 of the detection component 3 converges the incident light of the detection component 3 onto the photon detector 31 of the detection component 3. After being excited by light, the photon detector 31 outputs an electrical signal indicating that it has been triggered to the signal analysis component 4. The signal analysis component 4 acquires the number of times each of the four photon detectors 31 is excited per unit time. Based on the preset calculation method and photon event threshold, it determines whether the beam of light includes the target light and determines the object point distance corresponding to the target light.

[0103] In addition to the two cases mentioned above, when the beam splitter 2 has multiple beam-splitting output paths, the number of light-incident ends of the beam splitter 2 and the number of light-incident ends of the detector 3 on the beam-splitting output paths can be arbitrarily combined. For example, when the beam splitter 2 has five beam-splitting output paths, there can be three light-incident ends of the beam splitter 2 and two light-incident ends of the detector 3 on these five beam-splitting output paths. When the beam splitter 2 has multiple beam-splitting output paths, there may be neither light-incident ends of the beam splitter 2 nor light-incident ends of the detector 3 on the beam-splitting output paths. The light in these beam-splitting output paths can be absorbed by the housing 11, absorbed by the light-absorbing element installed on the housing 11, or leave the inside of the receiver body 1 through the light-emitting port provided on the housing 11.

[0104] This application provides a lidar system, which includes a laser emitter and a laser receiver. The laser emitter emits laser light, which is reflected upon detecting an external object, forming a target beam. Simultaneously with the laser emitter emitting the laser beam, the laser receiver begins receiving the external light and initiating detection. The laser receiver sends the detected object distance to the lidar's processor. The processor determines the spatial position of the object based on its angle and distance information, and aggregates all object positions to output point cloud data.

[0105] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A laser receiver, characterized in that, The laser receiver includes a receiver body (1), multiple beam splitting components (2), multiple detection components (3) and a signal analysis component (4). Each beam splitting component (2) includes an input end and multiple output ends, which are used to split the light entering the input end into multiple beams according to a set beam splitting ratio and emit them through the multiple output ends. The signal analysis component (4) is electrically connected to the multiple detection components (3). The plurality of beam splitting components (2) and the plurality of detection components (3) are installed inside the receiver body (1); The multiple beam splitting components (2) include a first beam splitting component (21), a second beam splitting component (22), and other remaining beam splitting components (2). The light input end of the first beam splitting component (21) is located on the incident light path of the receiver body (1), and the light input end of the other beam splitting component (2) is present on at least one beam splitting output light path of the first beam splitting component (21). The light input end of the second beam splitting component (22) is located on the beam splitting output light path of the other beam splitting component (2), and the detection component (3) is present on each beam splitting output light path of the second beam splitting component (2). The light input end of the other beam splitting components (2) is located on the beam splitting output light path of the beam splitting component (2) other than the second beam splitting component (2), and the light input end of the beam splitting component (2) is present on at least one beam splitting output light path of the other beam splitting component (2). Each detection component (3) is located on the beam-splitting output path of any beam-splitting component (2) where there are no other beam-splitting components (2); The signal analysis component (4) is used to count the number of excitations corresponding to different object distances for each detection component (3) based on the excitation signal sent by each detection component (3), determine the total number of excitations corresponding to each object distance based on the number of excitations corresponding to different object distances for each detection component (3), and determine the object distance as the detection result based on the total number of excitations corresponding to each object distance.

2. The laser receiver according to claim 1, characterized in that, The detection component (3) has an incident end on the output optical path of all beam splitting components (2) except for the beam splitting components (2) of other beam splitting components (2).

3. The laser receiver according to claim 2, characterized in that, Each beam splitting component (2) has two beam splitting output paths; In addition to the second beam splitting component (22), each beam splitting component (2) has an input end of another beam splitting component (2) in one beam splitting output path and an input end of the detection component (3) in the other beam splitting output path; The second beam splitter (22) has an input end of the detector (3) on each of the two beam splitting output paths.

4. The laser receiver according to claim 1, characterized in that, The receiver body (1) includes a housing (11) and an incident lens (12). The beam splitter (2) and the detector (3) are installed inside the housing (11); The light entrance lens (12) is installed at the light entrance port of the housing (11).

5. The laser receiver according to claim 4, characterized in that, The incident lens (12) includes a first diverging lens (121) and a filter (122) stacked together.

6. The laser receiver according to claim 1, characterized in that, The detection component (3) includes a photon detector (31) and a converging lens (32); The converging lens (32) is located at the light inlet of the photon detector (31).

7. The laser receiver according to claim 1, characterized in that, The beam splitting component (2) is a beam splitter.

8. A lidar, characterized in that, The lidar includes a laser receiver as described in any one of claims 1-7.

9. A method for detecting the distance between object points, characterized in that, The method is applied to a laser receiver, which includes a receiver body (1), multiple beam splitters (2), multiple detectors (3), and a signal analysis unit (4). Each beam splitter (2) includes an input end and multiple output ends, used to split the light entering the input end into multiple beams according to a set beam splitting ratio and emit them through the multiple output ends. The multiple beam splitters (2) and the multiple detectors (3) are installed inside the receiver body (1). The multiple beam splitters (2) include a first beam splitter (21), a second beam splitter (22), and other remaining beam splitters (2). The input end of the first beam splitter (21) is located on the incident light path of the receiver body (1). At least one beam splitter of the first beam splitter (21) is... The light output path contains the light input end of the other beam splitter (2); the light input end of the second beam splitter (22) is located on the beam output path of the other beam splitter (2), and the detection component (3) is present on the beam output path of the second beam splitter (22); the light input end of the other beam splitter (2) is located on the beam output path of the beam splitter (2) other than the second beam splitter (22), and the light input end of the beam splitter (2) is present on at least one beam output path of the other beam splitter (2); each detection component (3) is located on the beam output path of any beam splitter (2) where no other beam splitter (2) exists, and the signal analysis component (4) is electrically connected to the plurality of detection components (3). The method includes: The beam splitter (2) splits the signal light entering the laser receiver; The detection component (3) receives the split signal light, and when excited by the split signal light, it sends an excitation signal to the signal analysis component (4); The signal analysis component (4) counts the number of excitations corresponding to different object distances for each detection component (3) based on the excitation signal sent by each detection component (3), determines the total number of excitations corresponding to each object distance based on the number of excitations corresponding to different object distances for each detection component (3), and determines the object distance as the detection result based on the total number of excitations corresponding to each object distance.

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